1. Field of the Invention
The present invention relates to a thin film capacitor having a device structure for suppressing peeling between an insulating film and a substrate.
2. Description of the Related Art
A thin film capacitor is widely used in semiconductor devices, mounting circuit boards, electronic circuits, and so on. As a device structure of the thin film capacitor, various structures are being studied in light of high reliability. For example, Japanese Patent Application Laid-Open No. 2006-5293 proposes the following device structure as a device structure of a thin film capacitor having a laminate structure that is formed by laminating a lower electrode, a dielectric film, and an upper electrode in sequence on a substrate. In the proposed device structure, an insulating resin layer that has an opening for exposing the dielectric film and covers a periphery of the dielectric film is formed, and the upper electrode is laminated on the dielectric film exposed from the opening of the insulating resin layer. According to such a device structure, a poorly covered portion of the dielectric film between the lower electrode and the upper electrode can be covered with the insulating resin layer, so that a decrease in breakdown voltage can be suppressed.
[Patent Document 1] Japanese Patent Application Laid-Open No. 2006-5293
However, in the device structure disclosed in this patent document, the lower electrode has steps, and so a thickness of the insulating resin layer covering the laminate structure on the lower electrode and a thickness of the insulating resin layer covering the substrate and a side surface of the lower electrode are different. Such a difference in thickness of the insulating resin layer affects a stress generated due to a difference between a thermal expansion coefficient of the insulating resin layer and a thermal expansion coefficient of the lower electrode, and can cause peeling of the insulating resin layer on the side surface of the lower electrode.